In certain types of document handling operations it is desirable to be able to re-orient a document during its transit along a predetermined feed path. For example in certain types of mail handling equipment wherein vertically disposed mixed size mail pieces are stream fed in a horizontal direction along their lower edges it is occasionally necessary to re-orient a flat mail piece that happens to have its long dimension extending vertically rather than horizontally. In such a situation the document or mail piece must be rotated or turned in its own plane through approximately 90 degrees so that the said long axis of the horizontally moving document is now horizontal. In other types of mail handling operations, such as stamp cancelling, it is desirable to be able to change the position of a mail piece being transported from a postage stamp "leading" to a stamp "trailing" condition. In this situation the letter or other flat mail piece must be turned through 180 degrees or end for end during the course of its feed movement to the stamp cancelling station.
Prior art document handling devices that are capable of producing such 90 and/or 180 degree position shifting operations have not only been somewhat complex and expensive but have also had a tendency to impose rough physical treatment on the mail piece as the latter accommodates the various rubbing and/or flexure forces required for such positional shifting. Also the prior art devices in most cases require the document to be re-aligned with respect to the feed deck or initial feed path after being rotated through such 90 or 180 degree turns.